Alternate Names

PBk6—Lamp Black

Pigment Type

inorganic

Chemical Name

carbon

Chemical Formula

C

Properties

Lamp black is a very opaque, heavily staining black pigment that does not have much covering power. It is typically the most opaque black in watercolor form. Though a very pure black, it tends to muddy slightly in mixtures, is one of the slowest drying pigments in oils, and should not be used under other colors.

Permanence

Lamp Black is very lightfast and absolutely permanent. It is used in all techniques in permanent painting.

Toxicity

Lamp Black is slightly toxic by skin contact and inhalation. It is a possible human carcinogen.

History

Lamp Black is a carbon based black traditionally produced by collecting soot (known as lampblack) from oil lamps. It is the black found in Egyptian murals and tomb decorations and was the most popular black for frescoing until the development of Mars Black.

Alternate Names

PB15—Phthalo Blue

Pigment Type

organic

Chemical Name

copper phthalocyanine

Chemical Formula

C32H16CuN8

Properties

Phthalo Blues are pure and clean primary blues with superior covering power. They have a very high tinting strength and tend to overwhelm other pigments, but if color strength can be controlled, they make predictable mixed colors. In oil form, blues are very deep and slow drying. When mixed with other colors or if chlorine is added, Phthalo Blue quickly tends towards green. When using alone, mix with some white, as Phthalo Blue can be semi-transparent and almost black on its own. It is among the most compatible of modern colors with mineral colors and is considered more reliable than Prussian Blue, while sharing the same physical and color properties. Phthalo Blue is a good color for glazing.

Permanence

Phthalo Blues are completely lightfast and stable and are permanent for all paint uses. They are currently used in inks, coatings, and many plastics due to their stability and are considered a standard pigment in printing ink and the packaging industry.

Toxicity

Phthalo Blues have no significant hazards, although those made before 1982 contained some PCBs (polychlorinated biphenyls).

History

Developed by chemists using the trade name Monastral Blue, the organic blue dyestuff now known as Phthalo Blue was presented as a pigment in November 1935 in London. Its discovery was accidental. The dark color was observed in a kettle where a dye was being made from a British dyestuff plant. The demand for such a pigment came from commercial printers who wanted a cyan to replace Prussian Blue.